


Liquid Nitrogen

by Obotligtnyfiken



Series: Chickens coming home to roost [3]
Category: Sherlock (TV)
Genre: Champagne, Evil Mary, Gen, Mind Games, Revenge, Revenge is a dish best eaten cold, not john's baby
Language: English
Status: Completed
Published: 2017-06-26
Updated: 2017-07-03
Packaged: 2018-11-19 12:03:56
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 3,576
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11313009
Author URL: https://archiveofourown.org/users/Obotligtnyfiken/pseuds/Obotligtnyfiken
Summary: After John and Mary's wedding, Sherlock is in need of a distraction. But you should be careful what you wish for.





	1. Heat

**Author's Note:**

> UPDATE: I have now decided that this fic belongs to the series Mary, Mary, Quite Contrary. They also belong to the series Chickens Coming Home to Roost (see below).
> 
> This fanfiction takes place between The Sign of Three and His Last Vow, the second and third episodes of season three of BBC’s Sherlock. It is inspired by the prompt “Revenge is a dish best eaten cold” + liquid nitrogen that I got from a friend.
> 
> The prompt is based on one of my “Moffat’s Chickens”: twelve ideas from the hiatus about what Steven Moffat could have meant when he said in an interview that chickens were coming home to roost in s4. Link for Moffat's Chickens: https://obotligtnyfiken.tumblr.com/post/138370350688/master-post-for-moffats-chickens
> 
> I do not own these characters. This work is for entertainment purposes only.
> 
> A big thank you to wetislandinthenorthatlantic for beta reading!

Sherlock longed for his coat in the summer heat of Baker Street. He could have put the cigarette pack in the coat pocket, hiding it. He could have popped its collar, shielding his neck from the scorching sun. But the thick wool was simply too warm on a day like this. Maybe he should ask his tailor to make him a summer coat in some heat resistant material. He made a mental note to research the temperature control properties of performance fabrics.

The shiny black door of 221 B was so hot to the touch that Sherlock instinctively checked his fingertips for blisters. He ran his thumb over the pads of the fingers on his left hand, but he felt nothing but calluses from composing and rehearsing, again and again, the wedding waltz of John and Mary Watson. His fingers felt sore today, despite the fact that he had only had time to rehearse a few times yesterday morning before putting on his battle dress. Perhaps he had unconsciously pressed too hard on the fingerboard when he gave the performance of his life at the reception last night.

Sherlock closed the door behind him and relished the relatively cool air of the hallway. His eyes had not yet adapted to the dark, so he reached blindly for the mail that Mrs Hudson always left for him on the side table. To his surprise, there was a familiar box on top of the envelopes and restaurant menus. He looked down at it, his night vision restoring as the rhodopsin regenerated in the rods of his eyes. It was a small, rectangular box covered in red wrapping paper and tied with a black silk rope.

He turned the box over in his hands for a moment, contemplating an appropriate emotional response. How does one prepare for a box like this? Last time, he had been so full of himself, still confident of his superiority over everyone and everything, despite the fact that he had just made a complete fool of both himself and poor Molly Hooper in front of an entire Christmas party. And then, he had opened the box, found the phone and realised that Irene Adler was dead.

Only, she hadn't been dead. He used to wonder, during those lonely nights in dingy hotel rooms in Eastern Europe, if he had gotten the idea to fake his death from her. Two years on the hunt does something to a man, and Sherlock had felt his hubris being chipped away with every near miss and every half-mangled kill. He wasn't a hero and he definitely wasn't a superhero. He was just a man who had stolen the plot from a woman who beat him.

Sherlock shook his head to rouse himself. It didn't do to dwell.

This time, the box wouldn't contain a phone. It was too light for that. The faint rustle from within indicated two kinds of paper, one smaller, heavier piece, surrounded by another, more lightweight paper. He took a breath and opened it.

A small white calling card was resting in a nest of artfully rumpled dark red tissue paper. In the middle, the astronomical symbol of Venus was printed in glossy black. The Woman. As if she knew what he called her in private.

He smoothed his thumb over the symbol, feeling the gloss varnish that made the ink shiny black. He really ought to visit Fred soon to get an update on the latest products in the printing world. And on greyhound racing, as the man seemed incapable of stopping himself from talking about either subject.

On the other side of the card, written with a fountain pen and standard blue ink, was an address, the name Ms Smith and a time: 14:00. Two o'clock — this afternoon, presumably. There was not much that could be deduced from the card or its wrappings, except that she was obviously making an effort to exude her usual air of luxury, but was having to make do with materials bought at Paperchase. For a moment, Sherlock tried to pretend that he was considering whether to go or not, but he soon gave up. He was much too desperate for distractions to stop himself.

Lost in thought, Sherlock started up the stairs to go change his shirt.


	2. Sweat

The address turned out to be one of those expensive restaurants that try to attract the rich and the beautiful, but end up making most of their money from overseas tourists with rumpled clothes and a wide-eyed fascination with anything that reminds them of Queen Victoria or Miss Marple. However, what it lacked in sophistication, it made up for in air conditioning. Sherlock relished the rapid cooling of his decidedly moist shirt. He had started to regret choosing the flattering — but very tight — dark red one in this heat, but when meeting with such an opponent, he needed whatever armour his wardrobe possessed.

The maître d’hotel looked tired and resigned, but perked up at the sight of Sherlock’s impeccable suit. No doubt he longed to put a tie around Sherlock’s neck … no, actually. He would prefer if Sherlock opened another shirt button, even if he would never admit it if asked.

“I'm here to meet Ms Smith,” Sherlock said before the man could start flirting. 

“Of course. Please follow me.”

Sherlock was lead to a round window table with the chairs placed at an angle, so that two could sit next to each other, people watching, without turning away from each other. He declined a drink with a murmured “Not at the moment, thanks.” 

Ten minutes later, Sherlock was squirming uncomfortably in his jacket and wishing that he had smoked a cigarette before he went in. 

Five more minutes and Sherlock was crawling out of his skin. He was out of guests to deduce and he could feel his fingers start to twitch. 

Finally, he heard the sound of clicking heels on the restaurant floor. It felt like music in the din of the restaurant. The heels definitely belonged to The Woman, but something was a bit off. She wasn’t keeping her usual pace, but it was not a slow, sultry walk. Sad? Lonely? Difficult to tell from sound alone.

Sherlock kept his eyes on the road outside the window until he felt a sharp nail scratching the back of his neck. He turned his head and saw Irene Adler walk past to sit down next to him. She looked as stunning as always, with a billowing, asymmetrical white silk shirt tucked into a tight tan skirt with a red leather belt. Her lipstick was the same colour as her belt, and with a jolt Sherlock realised that the blood red colour exactly matched his shirt. They looked like a couple. Had she done it deliberately? Had she watched him arrive and chosen her outfit to match him? Was he that predictable? Or had he subconsciously deduced what lipstick colour she was likely to choose, and picked a shirt to match? Why had he done that? Sherlock was just about to shake his head to clear it from the paranoia, when he stopped himself. She had seen right through him before. It wouldn’t do to let her do so again. 

Irene was looking at him with an amused expression on her face. She beckoned for the waiter, who came over within seconds. He had probably been watching her since the moment she walked in.

“A bottle of Dom Ruinart Rosé, please.”

“What are we celebrating?” Sherlock asked when the waiter had left. 

“We are not celebrating. I want champagne,” Irene said with a dangerous gleam in her eyes.

Sherlock looked her over, trying to decide her intent. She had clearly put her hair up by herself, so her partner was not at home. Had they broken up? No. Her tense facial expressions and stiff back reflected her feelings towards Sherlock, not a broken heart. The buttons on her shirt said “taken” rather than “looking”, she was wearing her lipstick like a trademark, not like a signal, and she was ignoring the looks from the guests around them as if she genuinely wasn't interested. 

Sherlock turned his attention to the hostile tension around her eyes. Why was she upset? Why now? 

The pieces clicked together in Sherlock's head. There was a threat and her partner was in hiding, living somewhere else for her safety. Irene was blaming Sherlock for that. He relaxed a little, the deduction making him feel safer. 

“How was the wedding? Are you hungover today?” she asked.

“No,” he answered tersely. 

The champagne arrived and Irene started drinking the pink, bubbly wine slowly, ignoring Sherlock and watching the street as if the people there were interesting. He schooled himself to be still — another useful skill from abroad that he wished he hadn't been forced to learn. 

The restaurant reminded him of stakeouts in Paris, drinking wine to keep up appearances — the cheapest white wine on offer since he had to make funds last. It had tasted marvellous, even though he usually didn't like white wine. That's Paris for you. He had kept his patience through deducing the passers by and daydreaming about returning home to John. He had thought about finding a French case for them so that they could sit together drinking wine and watching Paris in the sunshine. 

Finally, Irene spoke. 

“Are you familiar with liquid nitrogen?”

His newly learned patience wore thin at the nonsensical question. “Yes — ?”

“It's very useful.”

“Yes, I know. I have used it on several occasions to preserve tissue samples for later testing.”

“Did you know that fertility clinics use it to preserve sperm for future use?”

The vicious smirk on Irene’s red mouth made beads of sweat break out at the back of Sherlock's neck, despite the artificially cool air. “Everybody knows that. Why are we having this conversation?”

Irene's smirk turned into a cold smile and she pointed to the alley across the street. “Because those are empty containers for liquid nitrogen and on the other side of that door is a fertility clinic. I am acquainted with the manager — in a manner of speaking. And guess who visited this clinic nine weeks ago for an insemination, for which her husband provided a sample on site.”

A few sweat beads started running down from Sherlock's neck, landing in a pool at the small of his back. 

“It was Mary Watson, née Morstan! Now that would be a nice bit of gossip on its own, of course, but it is nothing compared to the rest. You should sit back, Sherlock. I have a story to tell.”


	3. Chill

Irene put her champagne glass down and turned slightly towards Sherlock so that her knee touched his under the table. “Mary Watson, or Mary Morstan, as her name was at the time, checked into the clinic under the name of Claire Porter and she was accompanied by a man who was decidedly not John Watson.”

The sweat on Sherlock’s back suddenly turned cold. He tried not to shiver.

Irene was looking expectantly at him, waiting for a response, but Sherlock didn’t say a word. He wasn't sure he could trust his own voice — or his mind. He had tried so hard not to deduce Mary, that it felt like the neurological pathways about her were in a gridlock. Even his deduction of her pregnancy last night had been an accident, a slip of his mind and his tongue in front of the entire wedding party.

Realisation dawned in Irene’s eyes. “You already knew about the pregnancy. That was early. Most women wait until the twelfth week to tell friends and family.” 

She looked him over again and then slapped her hand over her mouth with an exaggerated gasp. “You deduced it, didn’t you! Was John there?” Staring at him some more, she let her hand fall. “You did it at the wedding. I can’t believe it. I knew I should have sneaked in.”

Being deduced by Irene was an unsettling experience. She was both right and wrong at the same time, missing the point entirely. Sherlock wondered if this was how people felt about him.

“And I take it that the happy father was surprised? I would be too, if I was him. You see, I have to admit that I did a bit of research on that wedding of theirs. I couldn’t help myself when I saw how much effort you put into it. So I looked into the guests and I found that fellow David, Mary’s ex-boyfriend. You knew that he’s not actually an ex, didn’t you? I can’t believe Dr Watson has been falling for all those flimsy excuses of book clubs and drinks with friends.”

Sherlock looked down, his blood turning to ice. He had underestimated David. He had underestimated Mary. He had got it all wrong.

Irene gave up a shrill laugh. “Oh, no, you really are The Virgin, aren’t you! You thought he was just pining for her! How cute. I was sure you had figured it out when you made him stop Twitter-flirting with her, but it seems I overestimated you. Nice touch, though, making him believe an usher had to have a special meeting with the best man before a wedding.” She nodded slowly, as if she approved. 

“Anyway, David has a very nice portrait of himself in his Facebook profile. When I showed it to my friend the fertility clinic manager, he confirmed that this was indeed the Mr Porter who had visited their clinic about two months ago. No wonder David was so shaken up by your little threats. He thought you were on to him!”

Sherlock took a sip of his champagne to try regain his composure. The carbon dioxide popped uncomfortably in his pharynx and the liquid felt sour in his stomach. 

“Let’s play deductions, like you do with your brother!” Irene slapped her hands together in false enthusiasm. “Mary is obviously not as attached to John as she would like us to believe. She is definitely involved with David and the reasonable conclusion is that she is carrying his child. But why? Why marry John, but go to the trouble of having a child by David through insemination? Why not just have sex with him like normal people do?” She cocked her head and said condescendingly, “Go on Sherlock, you know you can do it.”

Before he realised what he was doing, Sherlock had started speaking. “Because she needed to time the conception exactly, so that she was definitely pregnant at the wedding, but not so far along that it would be inconceivable for her to claim that she didn’t know,” he muttered between gritted teeth. “Insemination is designed to maximise the potential for conception and would have a higher probability of success than regular intercourse.”

He lifted his head defiantly. “They were probably going at it like bunnies as well, just to be on the safe side.” The tremble in his voice at the end of the sentence was virtually undetectable.

“Exactly!” Irene exclaimed. “One wonders why she would go to so much trouble, but all conceivable motives are rather sinister.” Irene’s eyes turned cold. “And we can be quite certain that John knows nothing about it. He doesn’t take well to deception, your doctor. He would not have looked this happy and content at his wedding if he had known that his blushing bride is deceiving him. He has been put through enough deception from those close to him, don’t you agree, Sherlock?”

Sherlock had goosebumps all over his body, chafing against his shirt and trousers, making him feel like the elastic in his socks and pants had suddenly shrunk. Last night, he had sworn that he would be there for both John and Mary. Well, actually, he had sworn to be there for all three of them. That included the unborn bastard child, something he was wildly unequipped for. He was caught in a web of responsibilities and he couldn’t see any way of moving either forwards or backwards without entangling himself further.


	4. Freeze

“Well, here we are,” Irene said. “I know what I know, and now you know what I know. But what would happen if John the happy husband knew? If you went out of here right now and told him?” 

She started counting off on her fingers. “He would be devastated. You would ruin their honeymoon, that’s for sure. Probably their marriage too.” She put her hands back in her lap demurely and let out a sorrowful sigh. “Poor John, he has been working so hard for this new start, for his one chance at a regular family and a normal life. Going to war, being wounded, PTSD and depression — and then you, bouncing him about like a rubber ball and leaving him to go jumping off a roof. After all that, he finally has a shot at being truly happy. Are you going to show up and take away the cup just as he is taking the first sip? He would never forgive you.”

Sherlock could feel himself start shivering. This was getting out of hand. He needed to deduce something, fast, something that would give him an advantage. 

“You know, he wouldn’t believe you if you told him that you didn’t realise that Mary and David are still having an affair. He thinks you can deduce absolutely anything. He will think that you knew all about it and didn’t bother to tell him. He thinks you are a genius but he doesn’t have much faith in your honesty or your care for other people’s feelings. With good reason.”

Sherlock felt frozen in place, and still the shivering continued. She was right. She was absolutely right. 

“You could wait until they come back from the honeymoon, of course. That way he will at least get to experience one short period of matrimonial bliss. But time is ticking and by then, they will certainly have told their families about the pregnancy. It would be a huge scandal if the truth came out. He would be even angrier at you then, for putting him through that.” 

Irene poured herself some more champagne. Sherlock watched transfixed as carbon dioxide gas nucleated into bubbles on the inside of the glass, dotting the pink liquid with gas globules. He wished he could pop like one of those bubbles, just disappear into thin air. 

“He doesn’t like scandal, does he, your doctor? He doesn’t have the same thick skin that you do, the arrogance.” She put her hand on his leg, confidentially. “That’s what keeps him away, you know, the way you make him believe that nothing he says or does gets to you.” 

Sherlock shuddered under her touch. He felt violated, not by her hand on his leg but by the information she was inserting into his brain. Knowledge he would have given anything to avoid. 

“No, it would probably be best to wait and see. She is bound to act soon, whatever her plans are. If you are lucky, she will dump John and he will come running back to Baker Street without your involvement.” She patted his leg and withdrew her hand. “I wouldn’t hold my breath, though. It might never happen. And if it does, he might still find out that you knew all along. He will never forgive you for that — not now, not in a month and not in three years. It would be better if you didn’t know,” Irene smiled serenely. “But you do. And you will have to live with the knowledge.”

Sherlock knew that she was right. She had chosen the perfect moment. Had she told him yesterday about Mary’s deceit, he would have found a way to stop the wedding. If she had told him a month from now, he would have scraped together the last of his courage and told John what he knew. But now he was trapped. He was choosing between hell, or purgatory with a high risk of ending up in hell anyway. 

Irene finished her champagne and picked up her handbag. “I will enjoy watching you squirm, Sherlock. I really will. And one day, I might get bored and tell him myself about his wife and about how you knew all along. He would believe that, wouldn’t he? He is always prepared to believe the worst about you.”

The word was out of his mouth before he could stop it. “Please.”

“Oh, Sherlock. That’s not like you.”

“Why are you doing this?”

“Because you made my life hell, Sherlock. I swore that I would get my revenge, even if I had to wait until hell froze over.” Irene rose slowly, smoothing her skirt. “It really is an amazing substance, liquid nitrogen. It will freeze absolutely anything. Even hell, apparently.” 

She started turning around to leave. Sherlock managed to stop himself from grabbing her wrist. 

“Just … just don’t tell him, Irene. Please.”

“I told you, all those years ago, that I would make you beg for mercy, twice.” Her smile had turned decidedly evil, and thoroughly satisfied. “I always get my way.” 

There was no music in the clicking of her heels as she walked away. Sherlock payed for the ridiculous pink champagne and left the restaurant with shaking hands. He went in search of cigarettes and an all consuming case to lose himself in. It didn't take long until Lady Smallwood gave him Magnussen.


End file.
